Process of dewatering peat



stares rersnr c erics.-

GEORGE SGI-IRGTER, OF DENVER, COLORADO.

PROCESS OF DEWATE-RING PEI-AT.

No Drawing.

This invention relates to pro waterii'ig peat, an obyect oi; the in cess of devention being; to reduce the peat to a con'u'nerciall'y dry as a fuel, as a. fcrt other industri adapted.

of pea form for e board, or for any tion to which it may be Heretofore. the drying ilizer, as a a1 apphcat has been a slow process and it has not been commercially possible to produce a dry 1' than twenty or thirty percent wa without the application of heat. improved process, water more moved from the peat, and amou )eat of less ter content With my readily rcnts of less than tiftecn'per centwater content a re easily and commercially attainable.

I it in its natural state is a b blach .vni sh to deposit formed by the :mcumulation of the slow decay of vegetable matter under water in bogs or swamps. while in some variet cs few tincuishcd. follows fibers Carbon c. Mun..- Hyd rog'en is Oxygen Nitrogen Sulphur H Specific gravity It is often fibrous can be dis A typical peat analysis is as I do not wish to be restricted in the use of the term peat to any time or L 1. SLZRL of tie D composition of the plant matter, but I desire to protect broadly the use of such materials in this process of dewatering.

The typical microscopic oxan'iination of the fiber or particles shows lcon formations in the cellular t numerous balissnes with microscopic globules of included water.

Peat in the average well drained bog will contain from eighty-five to ninety per cent water. Attempts to remove the tent by pressure, artificial drying.

water conosmosi...

of pressure either in a hvdraul ic or filter press below sixty per cent. All attempts by osmosis or through the peat mass have f economic results.

ailed by passing an electric current to produce The air drying of peat. has been attempted by the Canadian Government operating on a well drained bog,

by first mining and macerating the peat and spreading the same on the ground about six inches deep.

lVith such Application filed July 13, 1925. Serial No. 43,397.

an experiment from thirty to ninety days were required, according to the weather con.- ditions, to reduce the moisture content in the peat from thirty to forty per cent.

A piece of ground 'i'i'O feet long, 12 feet wide and 6 inches deep will contain sixteen tons of air-dried peat. Theresults of such experiments by the Fuel Testing Depar ment of the Janadian Government to date show clearly thatthe greater the degree of nilverizing the slower the drying, and the entire method is too expensive for competition with other material.

Peat possesses the properties of a colloid. To remove the water from it requires the removal of water from the interstices between and the surface of each particle, from such microscopic globules as exist and from the interior of the colloid, which is present with swelling. The ordinary relation of particle to particle is such that liquid cannot readily diffuse to the surface. The colloidal character of peat may render the surface somewhat impenetrable to water.

It is the purpose therefore of my invention to dewater the peat economically and give results which have never before been accomplished.

I utilize the principles of grinding, coagulation, osmosis, and compression to produce the condition for ready drying of the mass. It is my endeavor to grind the product to eliminate microscopic inclusions of water and to break down any frail structure of low diifusibilit-y to water and to produce a closely packed, solid mass. To aid in the production of this solid mass, coagulation is used. In some measure, no doubt, the coagulatiug agent serves to dehyrdate the colloidal particles by reducing the swelling, and that is one example of the principle of osmosis. It may also react cl'ieinically with a constituent of the peat to produce flocculation. I find that the later addition of a material such as lime will cause further exudation of water from an apparently dry peat mud. And, finally, I utilize compression, to produce the compactness necessary to make diffusion of water from the interior of the surface and to produce a solid of good physical strength. In some cases, I add fibre to the ground peat to serve as drying capillaries.

In carrying out my improved process the peat is best put in the. form of a wet slurry. In some cases, particularly in wet bogs, the

is drier Water is added to form the slurry, and the peat is ground.

During the crushing or agitation of the peat I add a coagulating agent. For example, I use calcium hydrate in sutficient quan tity to render the mass slightly alkaline. It the finely ground pulp is allowed to stand, only a small amount settles out, the balance remains in suspension and can only be liltered With great difiiculty, which is iinpractical in a commercial Way; but this finely ground peat pulp, to which has been added the coagulating agent, either in the process of grinding or to the pulp after the peat has been ground, coagulates and settles very quickly and is very easily filtered down to a moisture content of sixty or eight-y per cent. The mass is then decanted or filtered by removing the excess ater. The decant ed or filtered mass is then dried, and before the drying process an amount o'l drying agent, such as burnt lime or an alkali, is added. Without such addition to the de canted or filtered mass the drying action is not so rapid.

The quickest drying method is accomplished by first applying, pressure to the mass, prepared as above described. Generally speaking, the greater the pressure the more rapid is the drying action. Atter pressure has been applied the mass is al.- loWed to dry by letting it stand in the open for several days.

The filtered peat is then molded or pressed and allowed to dry and the moisture con tent will drop about ten per cent per day until the moisture content is below ten per cent; It the filtered peat is spread out and not molded or pressed it dries more slowly.

Experiments made by adding to filtered coagulated peat, a iproximately one per cent of adrying agent such as burnt lime, and also enough dried peat less #16 mesh added so that the mixture can be molded an der greater pressure, the drying is still turther hastened.

It will therefore be noted that with my improved process for dewatering peat, the secret is adding to the peat a coagulating agent such as calcium hydrate, and preterably adding enough coagulating agent to make the original slurry alkaline, and then after deeantation or filtration adding a drying agent such as burnt lime or an alkali.

Hence, it is to be distinctly understood that I do not wish to limit myself to the exact steps of the process nor to the propertions of the ingredients but desire to cover broadly the idea of dewatering peat by the addition thereto (it a ceagulating agent. which may be calcium hydrate or it may be some other agent which would give the dcsired results.

I also desire to cover broadly the idea of adding to the decanted or filtered coagulated peat a drying agent such as burnt lime or an alkali, and I also Wish to cover broad ly the idea of adding an additional amount of dried peat or fibre to the mixture oil filtered, coagulated peat and drying agent, so that the mass can be molded under greater pressure to hasten the drying action.

I claim:

1. The process of dewatering peat com-- prising coagulating net meat in the term of a. slurry with just su'ltieient lime to render the mass siightly alkaline, deeaning the liquid from the slurry, adding a drying agent such as burnt lime to the decanted peat, compressing the decanted mass, and then drying the COJDPIQSSQCl mass in the atmosphere.

2. The process of dewatering peat comprising coagulating ivet peat in the term of a slurry with just smiicient lime to render the mass Slightly alkaline, decanting the liquid from the slurry, adding a quantity o'l dried peat or fiber, adding a drying agent such as burnt lime to the decanted peat, compressing the decanted mass, and then drying the compressed mass in the atmosphere.

GEORGE A. SUHROTER. 

